Table of Contents

1: Introduction
2: Communication between MODBUS devices
3: MODBUS REGISTER MAP
4: Serial Transmission Modes of MODBUS networks
4.1. ASCII Mode
4.2. RTU Mode
5: MODBUS MESSAGE FRAMING
5.1. ASCII Mode Message Frames
5.2. RTU Mode Message Frames
6: MODBUS ADDRESSES
7: MODBUS FUNCTIONS
8: MODBUS DATA FIELD
9: MODBUS ERROR CHECKING
9.1. Parity Checking
9.2. Frame checking
10: MODBUS EXCEPTIONS
11: MODBUS/TCP
12: MODBUS/TCP and Sena Products
13: Conclusion